Speech expressions are changing. I used to get them, and unfortunately still do. As a politeness, I find the “No problem.” response from the bag person to whom I said “Thank you” for bagging my groceries a little weird.

If the response is “No problem”, could there have been a problem?

If there could have been a problem, what would the problem have been? How would the bag person have responded.

Bag Person: “There was a problem. I wanted to go on break, or send a text to my friend.”

So, maybe the next time, I should say I have no problem if you had no problem.